local shader = love.graphics.newShader(nil, [[
    float sdCircle(vec2 p, float r) {
        return length(p) - r;
    }
    vec4 effect( vec4 color, Image tex, vec2 uv, vec2 pos )
    {
        float d = sdCircle(pos / 20.0 - 0.5, 0.5);
        float c = smoothstep(-0.01, -0.06, d);
        return vec4(1.0, 1.0, 1.0, c);
    }
]])
ImageMaker:make("circle20", 20, 20, shader)

local spf = ResourceSystem:loadSpriteFrame("circle20")
spf.left = 10
spf.right = 10
spf.top = 10
spf.bottom = 10